Clostridium piliforme infection (Tyzzer disease) in horses: retrospective study of 25 cases and literature review

Tyzzer disease (TD) is caused by Clostridium piliforme, a gram-negative and obligate intracellular bacterium. The disease occurs in multiple species. A triad of lesions, namely colitis, hepatitis, and myocarditis, is described in cases of TD in some species, such as rats and mice. We carried out a retrospective analysis of 25 equine cases with a diagnosis of TD; 24 of 25 cases occurred in foals <45 d old; the remaining foal was 90 d old. There were 12 males and 12 females; no sex information was available for one foal. The affected breeds were Quarter Horse, Thoroughbred, Arabian, Paint, and Hanoverian. Most of the cases (19 of 25) occurred in the spring. There were 9 cases of sudden death; the remaining animals had diarrhea, fever, distended abdomen, depression, weakness, non-responsiveness, and/or recumbency. Gross findings included icterus, hepatomegaly with acinar pattern, serosal hemorrhages, pulmonary edema, and/or fluid content in small and large intestine. Microscopically, all foals had severe, multifocal, necrotizing hepatitis. Necrotizing lymphohistiocytic colitis was observed in 10 of 25 foals, and multifocal necrotizing myocarditis was found in 8 of 25. Gram-negative, Steiner-positive, intracytoplasmic filamentous bacteria were observed in hepatocytes, enterocytes, and myocardiocytes, respectively. PCR detected C. piliforme DNA in the liver (24 of 24), colon (20 of 24), and heart (5 of 25). Our results indicate that necrotic hepatitis is the hallmark of TD in horses; the so-called triad of lesions is not a consistent characteristic of the disease in this species.     

6个枣品种枣疯病抗性与枣疯植原体迁移特性差异研究

[目的]探究6个枣树品种枣疯病抗性差异以及枣树体内植原体迁移特性差异,为抗枣疯病枣树品种的选择利用以及枣疯病的防治提供基础数据.[方法]通过采集携带植原体的鸡心脆枣接穗,嫁接到健康枣树砧木上,采用田间调查与普通PCR技术相结合方法,比较不同品种抗枣疯病情况与植原体在不同枣树品种中迁移情况.[结果]不同枣树品种发病时间不...     

新城疫病毒SXFP株的分离鉴定

从陕西富平某种鸡场发病鸡群中分离出一株流行毒株,经HA—HI试验和动物回归试验,确定分离到的病毒为鸡新城疫病毒（NDV）,命名为SXFP株。经过测定。SXFP株鸡胚半数致死量（ELD50）为10^9.0／0．1mL;鸡胚最小致死量的平均致死时间（MDT）为52．3h,对1日龄SPF雏鸡脑内致病指数（ICPI）为1．92,提示SXFP株为强毒株。血清HI交叉反应试验显示SXFP株和La Sota株存在较小的抗原性差异。     

FMDV OA/58病毒株VP3蛋白结构的模拟与分析

以口蹄疫病毒株OA／58 RNA为模板,反转录并扩增目的cDNA,然后与pMD18-T载体连接并转化JM109菌株,提取的重组质粒用凝胶电泳、PCR和BarnHⅠ、HindⅢ双酶切法鉴定。分析表明,口蹄疫病毒VP1、VP2、VP3和VP4在核苷酸水平上的变异率是无差异的（P〉0．05）;而它们在氨基酸水平上的变异率差异显著（P〈0．05）。该毒株与20株源于GenBank中的VP3氨基酸序列比较发现其保守区主要位于第1～24、26～35、37～43、45～57、61～122、124～173、175～209、211～220位。运用同源模建,OA／58 VP3蛋白三维空间结构可分为A,B,C3个结构区域。保守区氨基酸残基在维持VP3蛋白的空间构象和功能方面具有重要作用。     

黄瓜枯萎病抗性与防御系统几种酶活性关系的研究

以黄瓜6个不同抗性品系为材料,研究苗期感染枯萎病菌后,叶片组织内超氧化物歧化酶(SOD)、过氧化物酶(POD)、多酚氧化酶(PPO)和苯丙氨酸转氨酶(PAL)的活性变化。结果表明,POD,SOD,PPO活性变化曲线中存在2个酶峰,PAL活性变化曲线中存在一个单峰。抗病品系的4种酶的峰I值明显高于感病品系,表现出一致性,而且SOD和PPO酶活性的提高与抗性呈极显著正相关,POD和PAL酶活性的提高与抗性呈显著正相关。     

松材线虫病疫木不同伐除方式对森林植物群落演替的影响

采用标准地调查法,对不同立地条件下松材线虫病除治迹地生态系统的植物种类丰富度、密度、多样性指数、均匀度指数及垂直结构情况进行调查和分析。结果表明:立地条件的差异和疫木不同采伐方式对植物群落次生演替的进程和方向都有不同程度的影响。立地条件较好,无论是皆伐、择伐还是不采伐,除治迹地植物群落乔木层和灌木层较受害前纯林的种类丰富度和多样性指数都有一定程度的增加;而立地条件较差的,经皆伐后,植物群落的种类丰富度和多样性指数不仅没有增加,反而降至极低,原有松林群落向灌丛方向退化。     

高粱炭疽病研究进展

高粱作为中国主要的酿造原料之一,在国民经济发展中占据重要地位。高粱炭疽病是高粱的主要病害之一,在整个生育期中均可发病,且在温暖湿润的热带和亚热带栽种地区更易发生和流行,不仅影响植株的正常生长,严重时会引起产量的大幅下降和籽粒品质的劣变。多年来,高粱病理学家和育种家对高粱炭疽病病原菌菌株分离、病害发生流行规律、发生原因、寄主抗性利用和抗炭疽病基因定位等方面进行了广泛的研究,取得了一些进展。这些研究为炭疽病的生化防控以及培育抗炭疽病品种奠定了基础。开展高粱炭疽病研究,发掘更丰富多样的优异抗性种质资源,减少农药使用,不仅可以满足中国高粱产业对天然有机高粱原料的巨大需求,还可以推动高粱生产向高产优质转变。对高粱炭疽病的分布和发病症状、炭疽病病原菌侵染机理、病害发生流行规律及流行原因、抗性资源鉴定和高粱抗炭疽病基因定位的相关研究进展进行了综合分析和论述,以期从分子水平上更好地认识高粱与炭疽病病原菌之间的相互作用,为高粱炭疽病研究提供参考。     

国家科技攻关白菜抗病育种进展

从白菜病理学研究,抗病性鉴定,抗性遗传规律和抗病机理研究,抗病新品种的选育和推广淫,抗病育种技术研究等５个方面了国家科技攻关白菜抗病育种的主要进展,并对白菜抗病育种的发展趋势和前景进行了探讨。     

Relationship between apolipoprotein E gene polymorphism and sporadic Alzheimer's disease

AIM: To evaluate the association between apolipoprotein E(apoE) gene polymorphism and sporadic Alzheimer's disease (AD). METHOD: A case-control study was undertaken detecting the polymorphism of apoE by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP).RESULTS:(1)The frequencies of 3/4 genotype and 4 al ele in AD were significant ly higher than that in age-matched controls(P<0.05).(2)The frequency of G/G genotype for apoE IE1 in AD was significantly higher than that in age-mat ched control(P<0.05).(3)The apoE 4 al ele was associated with a tripling of the risk for AD compared with no 4 allele(odd ratio 2.932, 95%CI 1.379~6.226);Homozygosity of the G allele in IE1 was associated with adoubling of the risk for AD compared with the G/C and C/C genotypes(odd rat io 2.223, 95%CI 1.075~4.599).However, the IE1 G al ele is also closely associated with apoE 4.When the sample was split on the basis of apo Egenotype, the associat ion between IE1 G/G genotype and AD was no longer statistically significant.CONCLUSION: ApoE ε4 was a risk factor of AD, and the apparent association between IE1 G/G and AD is a consequence of the association between the ε4 and IE1 G/G genotype.     

A reovirus disease in cultured mud crab, Scylla serrata, in southern China

A reovirus, designated mud crab reovirus (MCRV), associated with large economic losses was recently isolated from marine cultured mud crab, Scylla serrata, in southern China. The complete viral particle is 70 nm in diameter, icosahedral and non-enveloped. The virus infects connective tissue cells of the hepatopancreas, gills and intestine in mud crab and develops in the cytoplasm. Hundred per cent mortality was observed in mud crab experimentally infected by intramuscular injection, bath inoculation and oral inoculation, while cohabitation infection caused 80% mortality. The viral genome consists of 13 linear dsRNA segments, with an electrophoretic pattern 1/5/7. The results of this study suggest that the virus is highly pathogenic and can be transmitted enterically as well as via the body surface of mud crab. Although the genomic organization of this virus is different from that of the other crab reoviruses, CcRV-W2 and DpPV, all three of these reoviruses have similar electrophoresis patterns. Therefore, MCRV may be a new member of the DpPV and CcRV-W2 group.